R. Sadatsuki

Isolation and Characterization of Multipotential Mesenchymal Cells from the Mouse Synovium

The human synovium contains mesenchymal stem cells (MSCs), which are multipotential non-hematopoietic progenitor cells that can differentiate into a variety of mesenchymal lineages and they may therefore be a candidate cell source for tissue repair. However, the molecular mechanisms by which this can occur are still largely unknown. Mouse primary cell culture enables us to investigate the molecular mechanisms underlying various phenomena because it allows for relatively easy gene manipulation, which is indispensable for the molecular analysis. However, mouse synovial mesenchymal cells (SMCs) have not been established, although rabbit, cow, and rat SMCs are available, in addition to human MSCs. The aim of this study was to establish methods to harvest the synovium and to isolate and culture primary SMCs from mice. As the mouse SMCs were not able to be harvested and isolated using the same protocol for human, rat and rabbit SMCs, the protocol for humans was modified for SMCs from the Balb/c mouse knee joint. The mouse SMCs obtained showed superior proliferative potential, growth kinetics and colony formation compared to cells derived from muscle and bone marrow. They expressed PDGFRá and Sca-1 detected by flow cytometry, and showed an osteogenic, adipogenic and chondrogenic potential similar or superior to the cells derived from muscle and bone marrow by demonstrating in vitro osteogenesis, adipogenesis and chondrogenesis. In conclusion, we established a primary mouse synovial cell culture method. The cells derived from the mouse synovium demonstrated both the ability to proliferate and multipotentiality similar or superior to the cells derived from muscle and bone marrow.

Synovial perlecan is required for osteophyte formation in knee osteoarthritis

The osteophyte associated with osteoarthritis (OA) is a bony outgrowth formed at the margins of the affected joint through endochondral ossification-like processes. However, the mechanism of osteophyte formation and its pathogenesis are unclear. Perlecan (Hspg2), a heparan sulfate proteoglycan, is expressed in many extracellular tissues and plays critical roles in skeletal development and diseases. The aim of the present study is to identify the role of synovial perlecan in osteophyte formation using perinatal lethality rescued perlecan-knockout mice (Hspg2(-/-)-Tg) wherein perlecan expression is lacking in the synovial and other tissues, except for cartilage. We analyzed the development of osteophytes in joints of Hspg2(-/-)-Tg mice in two different animal models: the surgical OA model, in which the medial collateral ligament was transected and the medial meniscus was resected, and the TGF-β-induced osteophyte formation model. In the surgical OA model, the osteophyte size and maturation were significantly reduced in the OA joints of Hspg2(-/-)-Tg mice compared with control mice, while OA developed on the medial side of the knee joints with no differences in the cartilage degradation score or synovitis score between control and Hspg2(-/-)-Tg mice. The reduced osteophyte formation in Hspg2(-/-)-Tg mice was associated with reduced cell proliferation and chondrogenesis. In the TGF-β model, the osteophyte size and maturation were also significantly reduced in Hspg2(-/-)-Tg mice compared with control mice. Our findings suggest that synovial perlecan plays an important role in osteophyte development in OA, and they provide insights that may facilitate the development of OA therapy.

Headless Compression Screw Fixation of Jones Fractures An Outcomes Study in Japanese Athletes

Background: Internal fixation is advocated as the primary treatment for fifth metatarsal Jones fractures in athletes; however, screw insertion site discomfort and refracture can occur especially in competitive athletes. The ideal implant has not been determined. Hypothesis: Headless compression screw fixation of proximal fifth metatarsal Jones fractures is an effective treatment approach especially in competitive athletes. Study Design: Case series; Evidence level, 4. Methods: We studied 60 athletes treated surgically with a headless compression screw for fifth metatarsal Jones fractures (mean age, 19 years). The mean follow-up time was 178 weeks. We evaluated the clinical and radiographic outcomes of headless compression screw fixation of Jones fractures. Results: All athletes returned to full activity. The mean time to start running after surgery was 6.3 weeks (range, 3-12.7 weeks), and the mean time to full activity after surgery was 11.2 weeks (range, 6-25 weeks). One athlete suffered a delayed union, which healed uneventfully. One athlete suffered a nonunion and underwent reoperation for a screw exchange to an autogenous bone graft harvested from the iliac crest. No screw breakage was reported. No athlete suffered a refracture or discomfort in the screw insertion site. Conclusion: Headless compression screw fixation of fifth metatarsal Jones fractures provided excellent results, allowing athletes to return to full activity without both screw insertion site irritation and clinical refracture.

The degeneration and destruction of femoral articular cartilage shows a greater degree of deterioration than that of the tibial and patellar articular cartilage in early stage knee osteoarthritis: a cross-sectional study

OBJECTIVE The aim of the present study was to examine whether the degenerative and morphological changes of articular cartilage in early stage knee osteoarthritis (OA) occurred equally for both femoral- and tibial- or patellar- articular cartilage using magnetic resonance imaging (MRI)-based analyses. DESIGN This cross-sectional study was approved by the ethics committee of our university. Fifty patients with early stage painful knee OA were enrolled. The patients underwent 3.0 T MRI on the affected knee joint. Healthy volunteers who did not show MRI-based OA changes were also recruited as controls (n = 19). The degenerative changes of the articular cartilage were quantified by a T2 mapping analysis, and any structural changes were conducted using Whole Organ Magnetic Resonance Imaging Score (WORMS) technique. RESULTS All patients showed MRI-detected OA morphological changes. The T2 values of femoral condyle (FC) (P < 0.0001) and groove (P = 0.0001) in patients with early stage knee OA were significantly increased in comparison to those in the control, while no significant differences in the T2 values of patellar and tibial plateau (TP) were observed between the patients and the control. The WORMS cartilage and osteophyte scores of the femoral articular cartilage were significantly higher than those in the patellar- (P = 0.001 and P = 0.007, respectively) and tibial- (P = 0.0001 and P < 0.0001, respectively) articular cartilage in the patients with early stage knee OA. CONCLUSIONS The degradation and destruction of the femoral articular cartilage demonstrated a greater degree of deterioration than those of the tibial- and patellar- articular cartilage in patients with early stage knee OA.

Reference intervals of serum hyaluronic acid corresponding to the radiographic severity of knee osteoarthritis in women

BackgroudWhile serum levels of hyarulonic acid (sHA) is known to be useful for a burden of disease biomarker in knee OA, it is far from practical. The reference intervals must be established for biomarkers to be useful for clinical interpretation. The aim of this study was to establish the reference intervals of sHA corresponding to the radiographic severity of knee OA for elucidating whether sHA can be useful as a burden of disease marker for individual patient with knee OA.Methods372 women with Kellgren & Lawrence grade (K/L) 1 through 4 painful knee OA were enrolled in this study. The patients included 54 with K/L 1, 96 with K/L 2, 97 with K/L 3, and 118 with K/L 4. Serum samples were obtained from all subjects on the day that radiographs taken. A HA binding protein based latex agglutination assay that employed an ELISA format was used to measure sHA. Age and BMI adjusted one way ANOVA was used to set the reference intervals of sHA.ResultsThe reference intervals for sHA corresponding to the patients with K/L 4 (49.6 – 66.5 ng/ml) was established without any overlap against to those with K/L 1, 2 and 3, while those with K/L 1, 2 and 3 showed considerable overlap.ConclusionsThese results indicate that sHA can be available as a burden of disease marker for the individuals with severe knee OA (K/L 4), while it is not for those with primary to moderate knee OA (K/L 1–3).

Perlecan is required for the chondrogenic differentiation of synovial mesenchymal cells through regulation of Sox9 gene expression.

We previously reported that perlecan, a heparan‐sulfate proteoglycan (Hspg2), expressed in the synovium at the cartilage‐synovial junction, is required for osteophyte formation in knee osteoarthritis. To examine the mechanism underlying this process, we examined the role of perlecan in the proliferation and differentiation of synovial mesenchymal cells (SMCs), using a recently established mouse synovial cell culture method. Primary SMCs isolated from Hspg2−/−‐Tg (Hspg2−/−;Col2a1‐Hspg2Tg/−) mice, in which the perlecan‐knockout was rescued from perinatal lethality, lack perlecan. The chondrogenic‐, osteogenic‐, and adipogenic‐potentials were examined in the Hspg2−/−‐Tg SMCs compared to the control SMCs prepared from wild‐type Hspg2+/+‐Tg (Hspg2+/+;Col2a1‐Hspg2Tg/−) littermates. In a culture condition permitting proliferation, both control and Hspg2−/−‐Tg SMCs showed similar rates of proliferation and expression of cell surface markers. However, in micromass cultures, the cartilage matrix production and Sox9 and Col2a1 mRNA levels were significantly reduced in Hspg2−/−‐Tg SMCs, compared with control SMCs. The reduced level of Sox9 mRNA was restored by the supplementation with exogenous perlecan protein. There was no difference in osteogenic differentiation between the control and Hspg2−/−‐Tg SMCs, as measured by the levels of Runx2 and Col1a1 mRNA. The adipogenic induction and PPARγ mRNA levels were significantly reduced in Hspg2−/−‐Tg SMCs compared to control SMCs. The reduction of PPARγ mRNA levels in Hspg2−/−‐Tg SMCs was restored by supplementation of perlecan. Perlecan is required for the chondrogenic and adipogenic differentiation from SMCs via its regulation of the Sox9 and PPARγ gene expression, but not for osteogenic differentiation via Runx2.

Reconstruction of a ruptured patellar tendon using ipsilateral semitendinosus and gracilis tendons with preserved distal insertions: two case reports

BackgroundAcute patellar tendon ruptures with poor tissue quality. Ruptures that have been neglected are difficult to repair. Several surgical techniques for the repair of the patellar tendon have been reported, however, these techniques remain difficult because of contractures, adhesions, and atrophy of the quadriceps muscle after surgery.Case presentationWe report the cases of 2 Japanese patients (Case 1: a 16-year-old male and Case 2: a 43-year-old male) with patellar tendon ruptures who were treated by reconstruction using semitendinosus-gracilis (STG) tendons with preserved distal insertions. Retaining the original insertion of the STG appears to preserve its viability and provide the revascularization necessary to accelerate healing. Both tendons were placed in front of the patella, in a figure-of-eight fashion, providing stability to the patella.ConclusionBoth patients recovered near normal strength and stability of the patellar tendon as well as restoration of function after the operation.

Osteoarthritis as a Cause of Locomotive Syndrome: Its Influence on Functional Mobility and Activities of Daily Living

Abstract“Locomotive syndrome” is defined as a condition associated with restriction in one’s ability to walk or lead a normal life due to a dysfunction in one or more of the parts of the locomotion system, including the muscles, bones, joints, cartilage or intervertebral discs. This syndrome especially refers to individuals who have come to need nursing care services because of problems with the locomotive organs, or those who have conditions which may require them to need such services in the near future. Recent epidemiological studies revealed that the one-fourth of elderly individuals who require special assistance or nursing care have locomotive disorders in Japan. Osteoarthritis of the knee (knee OA) and hip (hip OA), and osteoporosis and spinal canal stenosis due to spondylosis are three major locomotive disorders that cause elderly individuals require special assistance or nursing care. In this review, we focus on the effects of knee and hip OA on the lives of elderly individuals and the recent advantages in clinical research on the pathophysiology and management of these diseases.

Case series: Revision anterior cruciate ligament reconstructions using patellar tendon autografts

BACKGROUND Using intra-operative findings and clinical results, including return to play (RTP) at the pre-injury level, this study investigated the causes of primary graft failure after revision anterior cruciate ligament (ACL) reconstruction with bone-patellar-tendon-bone (BPTB) autografts. METHODS A total of 54 patients were followed for a mean of 38.2 ± 10.2 months post-surgery. Subjective and objective results were evaluated using single assessment numeric evaluation (SANE) scores, Lachman tests, KT-2000 arthrometer results, and pivot-shift tests. The change in each patients Tegner activity scale and RTP at the pre-injury level were also evaluated. RESULTS Inappropriate positioning of the tunnels was the most important reason (54%) for primary graft failure. After revision surgery, anterior knee stability was significantly improved (1.2 (mean) ± 1.2 (SD)mm vs 4.5(mean) ± 1.9 (SD)mm; P < 0.01). Two (4%) patients sustained revision graft ruptures while two (4%) sustained contralateral knee ACL tears. The rate of RTP at the pre-injury level was 67% (36 patients), and mean SANE scores at the time of RTP were higher than before surgery (74.8 ± 13.8 points vs 24.1 ± 16.4; P<0.001). The average time from primary graft failure to revision surgery was shorter (12.2 (mean) ± 4.0 (SD) vs 37.6 (mean) ± 8.8 (SD)months; P < 0.01) and the ratio of major cartilage injury was lower (39% vs 83%; P < 0.05) in the RTP group than that in the non-RTP group. CONCLUSIONS The time from primary graft failure to revision surgery and the extent of the cartilage injury are major factors in RTP after revision ACL reconstructions.

The MRI-detected osteophyte score is a predictor for undergoing joint replacement in patients with end-stage knee osteoarthritis

Abstract Objectives: The aim of this prospective cohort study was to examine whether MRI-detected osteoarthritis (OA)-structural changes at baseline could predict knee OA patients who would undergo total knee arthroplasty (TKA). Methods: In total, 128 end-stage medial-type knee OA patients were enrolled and followed up for 6 months. MRI using the whole-organ MRI scoring (WORMS) method, radiographic findings, visual analog scale (VAS) for pain and a patient-oriented outcome measure, and the Japanese Knee Osteoarthritis Measure (JKOM) were recorded at baseline. The area under the curve (AUC) was estimated to determine the discriminative value of the prediction models. Results: While 74 patients (57.8%) did not undergo TKA, the remaining 54 patients (42.2%) underwent TKA during this period. The AUCs of the receiver operating characteristic (ROC) curve for the activities of daily living (ADL) score evaluated by the JKOM ADL score [0.70 (95% CI: 0.60–0.79)] and osteophyte score [0.72 (0.64–0.81)] were 0.70 or greater. The JKOM ADL score (17/40) and the osteophyte score (30/98) showed relative risks (RR) of 2.61 (1.32–5.15) and 3.01 (1.39–6.52) for undergoing TKA, respectively. Conclusion: The osteophyte score detected by MRI, in addition to ADL score, was found to be an important factor in determining whether the patient should undergo TKA.